/*
 * SPI testing utility (using spidev driver)
 *
 * Copyright (c) 2007  MontaVista Software, Inc.
 * Copyright (c) 2007  Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License.
 *
 * Cross-compile with cross-gcc -I/path/to/cross-kernel/include
 */

#include <stdint.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>

#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))

static void pabort ( const char* s )
{
    perror ( s );
    abort();
}

static const char* device = "/dev/spidev1.1";
static uint8_t mode;
static uint8_t bits = 8;
static uint32_t speed = 500000;
static uint16_t delay;

static void transfer ( int fd )
{
    int ret;
    uint8_t tx[] =
    {
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0x40, 0x00, 0x00, 0x00, 0x00, 0x95,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
        0xDE, 0xAD, 0xBE, 0xEF, 0xBA, 0xAD,
        0xF0, 0x0D,
    };
    uint8_t rx[ARRAY_SIZE ( tx )] = {0, };
    struct spi_ioc_transfer tr =
    {
        .tx_buf = ( unsigned long ) tx,
        .rx_buf = ( unsigned long ) rx,
        .len = ARRAY_SIZE ( tx ),
        .delay_usecs = delay,
        .speed_hz = speed,
        .bits_per_word = bits,
    };

    ret = ioctl ( fd, SPI_IOC_MESSAGE ( 1 ), &tr );

    if ( ret < 1 )
        pabort ( "can't send spi message" );

    for ( ret = 0; ret < ARRAY_SIZE ( tx ); ret++ )
    {
        if ( ! ( ret % 6 ) )
            puts ( "" );

        printf ( "%.2X ", rx[ret] );
    }

    puts ( "" );
}

static void print_usage ( const char* prog )
{
    printf ( "Usage: %s [-DsbdlHOLC3]\n", prog );
    puts ( "  -D --device   device to use (default /dev/spidev1.1)\n"
           "  -s --speed    max speed (Hz)\n"
           "  -d --delay    delay (usec)\n"
           "  -b --bpw      bits per word \n"
           "  -l --loop     loopback\n"
           "  -H --cpha     clock phase\n"
           "  -O --cpol     clock polarity\n"
           "  -L --lsb      least significant bit first\n"
           "  -C --cs-high  chip select active high\n"
           "  -3 --3wire    SI/SO signals shared\n" );
    exit ( 1 );
}

static void parse_opts ( int argc, char* argv[] )
{
    while ( 1 )
    {
        static const struct option lopts[] =
        {
            { "device",  1, 0, 'D' },
            { "speed",   1, 0, 's' },
            { "delay",   1, 0, 'd' },
            { "bpw",     1, 0, 'b' },
            { "loop",    0, 0, 'l' },
            { "cpha",    0, 0, 'H' },
            { "cpol",    0, 0, 'O' },
            { "lsb",     0, 0, 'L' },
            { "cs-high", 0, 0, 'C' },
            { "3wire",   0, 0, '3' },
            { "no-cs",   0, 0, 'N' },
            { "ready",   0, 0, 'R' },
            { NULL, 0, 0, 0 },
        };
        int c;

        c = getopt_long ( argc, argv, "D:s:d:b:lHOLC3NR", lopts, NULL );

        if ( c == -1 )
            break;

        switch ( c )
        {
            case 'D':
                device = optarg;
                break;

            case 's':
                speed = atoi ( optarg );
                break;

            case 'd':
                delay = atoi ( optarg );
                break;

            case 'b':
                bits = atoi ( optarg );
                break;

            case 'l':
                mode |= SPI_LOOP;
                break;

            case 'H':
                mode |= SPI_CPHA;
                break;

            case 'O':
                mode |= SPI_CPOL;
                break;

            case 'L':
                mode |= SPI_LSB_FIRST;
                break;

            case 'C':
                mode |= SPI_CS_HIGH;
                break;

            case '3':
                mode |= SPI_3WIRE;
                break;

            case 'N':
                mode |= SPI_NO_CS;
                break;

            case 'R':
                mode |= SPI_READY;
                break;

            default:
                print_usage ( argv[0] );
                break;
        }
    }
}

int main ( int argc, char* argv[] )
{
    int ret = 0;
    int fd;

    parse_opts ( argc, argv );

    fd = open ( device, O_RDWR );

    if ( fd < 0 )
        pabort ( "can't open device" );

    /*
     * spi mode
     */
    ret = ioctl ( fd, SPI_IOC_WR_MODE, &mode );

    if ( ret == -1 )
        pabort ( "can't set spi mode" );

    ret = ioctl ( fd, SPI_IOC_RD_MODE, &mode );

    if ( ret == -1 )
        pabort ( "can't get spi mode" );

    /*
     * bits per word
     */
    ret = ioctl ( fd, SPI_IOC_WR_BITS_PER_WORD, &bits );

    if ( ret == -1 )
        pabort ( "can't set bits per word" );

    ret = ioctl ( fd, SPI_IOC_RD_BITS_PER_WORD, &bits );

    if ( ret == -1 )
        pabort ( "can't get bits per word" );

    /*
     * max speed hz
     */
    ret = ioctl ( fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed );

    if ( ret == -1 )
        pabort ( "can't set max speed hz" );

    ret = ioctl ( fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed );

    if ( ret == -1 )
        pabort ( "can't get max speed hz" );

    printf ( "spi mode: %d\n", mode );
    printf ( "bits per word: %d\n", bits );
    printf ( "max speed: %d Hz (%d KHz)\n", speed, speed / 1000 );

    transfer ( fd );

    close ( fd );

    return ret;
}
